Grinding machines for work on heavy workpieces



June 2, 1959 o. WALDRICH 2,388,839

GRINDING MACHINES FOR WORK ON HEAVY WORKPIECES Filed Nov. 15. 1954 Fig. 2

United States Patent Q GRINDING MACHINES FOR WORK ON HEAVY WORKPIECES This invention relates to an improvement in grinding machines in which heavy workpieces are supported in sleeve 01' like bearings, for example a heavy roll grinding machine.

In the grinding of heavy rolls these are mounted by means of their necks in supporting stocks in the grinding machine. The drive of the roll to be ground is effected through a jointed shaft or by a carrier which is driven from the face plate on the headstock spindle of the machine. Between the headstock and the driving motor a gear is provided adjustable within small limits.

' At the initiation of the drive, there is stationary friction between the roll necks and the bearing surfaces of the support stocks. The co-eflicient of friction at rest is, however, many times as great as that of dynamic friction, so that in starting the drive a multiple of the normal operating torque must be applied. The driving means and the gear for transmitting the drive to the base-plate, i.e., to the roll, has therefore to be designed to supply this multiplied starting torque and in relation to the requirements of normal operation has therefore to be excessively dimensioned by a corresponding factor.

,This disadvantage of the prior construction is overcome according to the invention by the provision, additionally to the main drive means for the roll to be ground, of an initial drive means of high reduction ratio which is used solely during starting up. A first result is that the output of the main driving means can be considerably reduced and the driving means can be provided with means for permitting slip so that under the high starting load the main drive means first slips and the actual starting up is effected by the initial drive means, an evening out occuring after a short time so that finally the whole load is taken over by the main drive means at normal speed, while conversely a slip coupling or free wheel or an uncoupling device is provided between the initial drive means and the masses to be moved, so that the action of the initial drive means occurs, in accordance with the invention, only during the first starting up period.

However, in further development of this basic concept the initial drive means can be coupled before starting and then be uncoupled when a speed suflicient for the main drive means is reached. In this embodiment the further advantage is obtained that the main drive means can be designed mainly with regard to the normal operating power so that during starting it only supplies that part of the power which corresponds to its normal output.

Such an arrangement can be made particularly effective by actuating the initial drive means by the main drive means, this according to the explanations above given being connected to the masses to be moved during the starting period. As soon as the above mentioned suitable speed of rotation has been reached by means of the initial drive means, this drive means is uncoupled and care must then be taken in accordance with this development of the invention that the main drive means be coupled at least immediately after the uncoupling of the initial drive means. The coupling of the main drive means can, however, be effected simultaneously with the uncoupling of the initial drive means and this so far as it can be practically done is to be preferred because the delay between the uncoupling of the initial drive means and the coupling of the main drive means must not be too great in order not to let the speed caused by the initial drive means fall. In this arrangement it is further advisable to provide a free wheel in the energy path from the main drive means through the initial drive means to the masses to be accelerated, so that coupling of the main drive means can take place even before uncoupling of the initial drive means.

Another mode of embodiment of the invention consists in providing the initial drive means with a separate driving motor of small power.

The above described bringing into and out of action of the initial drive means and main drive means can be effected either in dependence on the speed or by means of a delay relay the delay of which is adjustable, this latter method being particularly simple and economical.

While in the known roll-grinding machines the face plate is driven by a main driving motor through gearing regulatable within small limits and then through a V-belt drive to the face plate, it is advantageous to provide the initial drive means with a toothed wheel gear train, the last gear of which directly engages the face plate, e.g., by the meshing of gear teeth.

The coupling and uncoupling of the initial drive means can be eifected, for example by electro-magnetic operation of the parts. When toothed gears are used the last gear can be rocked round the periphery of the next to the last gear and can be brought by this rocking movement into engagement with the face plate, this rocking movement being effected by an automatic coupling device. Furthermore, the arrangement of the gearing in relation to the face plate can be such that the coupling device merely has to act for a short time to bring about coupling, the forces caused by the main driving motor and acting through the initial drive means on the face plate automatically holding these parts in engagement, and this engagement, for example by the use of a return spring or the like then automatically being released when power is no longer passing from the driving motor of the initial drive means and thence passing to the base plate but being provided directly through the main drive motor. It is further possible to use this uncoupling movement of the initial drive means simultaneously to switch off the initial motor.

The invention will be described with reference to an example illustrated in the accompanying drawing.

Fig. 1 is a diagrammatic side view of an arrangement according to the invention, while 7 Fig. 2 is a plan view of Fig. 1 partly in section.

The face plate 5 of a roll-grinding machine is driven by a main motor 6 through a gear 7 regulatable within the necessary limits for normal running from this to a V- groove belt pulley 8. The drive is conveyed through V-belts 9 to a larger pulley 10 and through a countershaft 11 to a small V-belt pulley 12 and through a further set of V-belts 13 to the face plate 5.

As will be seen from the part section on the right-hand side of the face plate 5 in Fig. 2, the face plate 5 has internal teeth 14 with which meshes a toothed wheel 15 which belongs to the initial drive means according to the invention. This initial drive means comprises a motor 16 of which through a worm 17 drives a worm wheel 18 to which is fast a small toothed wheel 19. Both wheels 18 and 19 are on a shaft journalled in fixed position while the wheel 15 by means of a link mounting 20 can be rocked around the periphery of the toothed wheel 19 and in this way can be brought into and out of mesh with the teeth 14 of the face plate 5.

The coupling movement is effected by means of an electromagnet device 21, such for example as a solenoid, which swings the link mounting 20 and thus the toothed wheel 15 through a pull rod 22.

The mode of operation of this construction is as follows. When starting up by means of a press button switch the main motor 6, and the initial motor 16 are switched on and the magnet 21 is energised so that the initial drive means 15-20 is brought into engagement with the face plate 5. After this position has been set up electro-magnet 21 is de-energised so that it is supplied with current for only a short time. As can be seen from the drawing the position of the link mounting 20 and the wheel 15 in relation to the toothed Wheel 19 and the teeth 14 of the face plate are so arranged that the forces which are transmitted through the gearing to the face plate maintain engagement as long as the drive is being transmitted by these parts.

It will be seen that the wheel rotates clockwise as seen in Fig. 1. Consequently, the torque reaction on the link mounting 20 tends to swing the link counter clockwise and thus deepen the mesh of the wheel 15 in the teeth 14. The pull rod 22 or some independent stop will limit the depth of mesh to a suitable value.

With increasing speed the supply of power is taken over increasingly by the main drive motor 6 so that the locking force between the initial drive means and the face plate gradually falls and upon reaching the maximum speed of the initial drive means the locking force ceases. Unmeshing can be effected by the weight of the parts.

I claim:

1. In a grinding machine having a rotatable face plate for holding a heavy workpiece to be ground, the combination, comprising a first motor constituting the normal driving motor for said face plate, means driven by said motor for rotating said face plate, a circular set of internal gear teeth formed on said face plate, a second motor constituting initial driving means for said face plate, a worm driven by said second motor, a Worm wheel driven by said worm, a drive shaft driven by said worm wheel, a transfer gear afiixed to said shaft, a driving gear pivotally mounted about said shaft and driven by said transfer gear, and means for selectively effecting operative engagement and disengagement of said driving gear with said set of internal gear teeth formed on said face plate.

2. In a grinding machine having a rotatable face plate upon which a heavy workpiece to be ground is secured, the combination, comprising, a first motor constituting the normal driving means for said face plate, means driven by said motor for rotating said face plate, a circular set of internal gear teeth formed on the periphery of said face plate, a second motor, a worm driven by said second motor constituting initial driving means for said face plate, a Worm wheel driven by said worm, a drive shaft afiixed to and driven by said worm wheel, a transfer gear mounted on said shaft proximate to said face plate, a driving gear pivotally mounted on said shaft and driven by said transfer gear, and. a solenoid opera- 4 tively coupled to said driving gear for effecting operative engagement of said driving gear with said set of internal gear teeth during the initial rotational period of said face plate by said first motor and for effecting disengagement of said driving gear therefrom thereafter.

3. In a grinding machine having a rotatable face plate upon which a heavy workpiece to be ground is secured, the combination, comprising, a first electrical motor constituting the normal driving means for said face plate, a gear train driven by said motor, a first pulley driven by said gear train, a second pulley driven by said first pulley, a third pulley driven by said second pulley, a belt about said third pulley and said face plate for effecting rotational movement of said member, a circular set of internal gear teeth formed within the peripheral extremity of said face plate, a second motor constituting an initial driving means for said face plate, a worm driven by said second motor, a worm wheel driven by said worm, a drive shaft atfixed to and driven by said worm wheel, a transfer gear mounted on said shaft and driven by said transfer gear, a driving gear pivotally supported from said drive shaft in mesh with said transfer gear, and a solenoid operatively coupled to said driving gear for pivoting said driving gear into engagement with said set of internal gear teeth during the initial period of rotational movement of said face plate thereby to assist said first motor in overcoming the stationary frictional forces tending to oppose rotational movement of said face plate, and for elfecting disengagement of said driving gear from said member thereafter.

4. In a grinding machine for rolling mill rolls and the like, a head stock, a face plate mounted for rotation in said head stock, the perpihery of said face plate being formed as a flange extending away from the face of said face plate, normal driving means for said face plate for driving said face plate when said grinding machine is in use drivingly connected to the exterior surface of said face plate, initial driving means for aiding in bringing the face plate, and a workpiece mounted in the grinding machine, up to operating speed, comprising a motor, a shaft parallel to the axis of said face plate and driven by said motor, a first gear on said shaft, said first gear being positioned Within but out of contact with said flange on said face plate, a second gear meshing with said first gear and mounted for rotation on a link pivoting on said shaft, so that said second gear will at all times mesh with said first gear, gear teeth on the inner surface of said flange adjacent said first and second gears, and magnet means to swing said link about said shaft whereby said second gear may be held in meshing engagement with the gear teeth on the inner surface of said flange until said face plate and the workpiece have attained a speed at which the normal driving means for the grinding machine can drive said face plate and workpiece.

References Cited in the file of this patent UNITED STATES PATENTS 990,999 McGuire et a1. May 2, 1911 1,116,096 Miller Nov. 3, 1914 2,029,094 De Vlieg et al I an. 28, 1936 2,525,915 Kuhn Oct. 17, 1950 

